The present invention relates to a motion picture filming process and a device to eliminate the contamination of photographic film, which leads to filming defects.
The imaging industry is very concerned about the quality of motion picture films. The various manipulations of the film, associated with effects due to aging, and as a result to modification of the film structure over time, lead to the conception of processes for utilizing the film in the best possible conditions.
In relation to this manipulation and aging, the removal of contamination particles on the film surface is important in many applications, such as the cleaning of photographic films utilized in image retrieval devices, in the manufacturing operations for photographic films, etc. Well-known systems for removing contamination particles from the film surface can be for instance based on the principle of compressed air blades or blade sections, or various suction systems.
U.S. Pat. Nos. 5,337,767 and 5,425,813 describe a device and its process intended to clean the film surface. The device comprises a particle transfer roller to clean the film, this roller being itself decontaminated by a system based on a bath of liquid cleaner. While drying means (waiting time between two cleanings, scraper blade) are planned, one of the disadvantages of this system is humidification of the film, by the particle transfer roller.
U.S. Pat. No. 5,447,170 describes a device for cleaning film, whose operation is based on the principle of roller vibrations, vibrations supplied by electric means, associated in part with polyurethane roller surfaces to facilitate the transfer of film particles onto them when the film is running, and in part with an improved cleaning system, consisting in running the film through a high humidity zone. One of the disadvantages of this device is the utilization of many particle transfer rollers.
U.S. Pat. No. 5,561,483 describes a system for cleaning the support surface of the film exposure aperture, mounted on a film projector or camera. The cleaning device comprises a polyurethane sheet or membrane that is applied momentarily by means of pneumatic pressure to the exposure aperture and then retracted, retaining the particles previously deposited on this film support surface. In this system, the film is not cleaned, but its support surface is exposure aperture.
European Patents 0 604 334 A1 and 0 658 828 A1 describe a material and associated processes for cleaning for example a film. The material making up the cleaner element is a polyurethane copolymerized with a charge control agent, offsetting the electrostatic phenomenon, and not migrating to the surface (risk of deposit on the cleaned surface); further, the last property improves the lifetime of the cleaning material.
The invention relates to a photographic recording process based on the principle of transferring the film particles onto a polyurethane surface, just before going in front of the exposure aperture.
The invention relates to a device for the continuous decontamination of motion picture film, just before its exposure.
In one particular embodiment, the system comprises:
two rollers with a polyurethane external surface, intended to decontaminate the film surface;
one rigid base support onto which the rollers are fixed; this support is fixed to the cartridge or camera body;
one rigid closing plate that, using attachment parts, holds the rollers onto the base support.
The invention has qualitative time saving advantages and enables financial savings to be made;
the shape of the particles will no longer appear on photographic shots, as they will be retained upstream of the exposure aperture;
the particles generated over time on the film due for instance to a change of the emulsion will be eliminated, as the means, the object of the invention, is utilized just before the film goes in front of the exposure aperture;
the camera downtime for cleaning will be less;
the quality inherent costs due to later rejection of photographic prints, to the need to reshoot, to cleaning time, will be substantially less.